Permanent magnetic direct current (PMDC) brush motors are used in a variety of applications where it is desired to keep electromagnetic interference (EMI) to a minimum. Typically, the motor housing is grounded in order to decrease EMI transmission to surrounding electrical devices. Conventionally, a grounding wire is typically disposed on the brush assembly. One end of the grounding wire is electrically connected to a power supply circuit of the brushes, and the other end extends to a periphery of the insulating brush holder. During assembly, the brush assembly is disposed at an open end of the motor housing, and an end cap of the motor is then disposed on an outside of the brush assembly to be connected to a motor housing. In a traditional connecting method, portions of the open end of the housing are crimped or otherwise plastically deformed over the edge of the end cap to secure the end cap to the housing.
After assembly, the grounding wire on the brush assembly is axially sandwiched between the peripheral edge of the end cap and the peripheral edge of the motor housing so as to be electrically connected to the motor housing. One shortcoming of such configuration is that a slit is formed at the connecting area between the end cap and the motor housing due to the presence of the grounding wire. In addition, in order to securely sandwich the grounding wire to ensure the close contact of the grounding wire with the motor housing, the end cap presses against the grounding wire after the end cap is mounted. This may lead to deformation of the end cap, or even a failure of securely mounting the end cap. On the contrary, if the end cap does not press firmly against the grounding wire, the ground wire may not effectively contact the housing, which may lead to an unstable ground connection.